Avastin helps in ovarian cancer but effects fade

MILAN (Reuters) - Roche's blockbuster drug Avastin helps women with ovarian cancer live longer without their disease getting worse, but its effect peaks at 12 months and then diminishes, researchers said on Monday.

Overall, the drug extends the time patients live without their disease getting worse by 1.5 months, Dr. Tim Perren from Leeds Teaching Hospitals NHS Trust, England, told the European Society for Medical Oncology (ESMO) congress.

There have been no significant new drugs for ovarian cancer since the mid-1990s and cancer doctors said Avastin could represent a step forward in managing the disease, although it is not the only new option being considered.

Other drugs are also starting to show encouraging signs in tests, including Amgen's AMG 386.

Mondher Mahjoubi, Roche's head of oncology, said ovarian cancer could add between 500 million Swiss francs and 1 billion ($500 million to $1 billion) to peak annual sales of Avastin, a product which sold some $6 billion worldwide in 2009 as a treatment for bowel, breast, lung and other cancers.

The bid by the world's largest maker of cancer drugs to expand the reach of Avastin has run into problems this year, following unsuccessful trials in prostate and gastric cancer, and doubts about its use in breast cancer.

Success in ovarian cancer may offset those setbacks, although there is some uncertainty about how willing doctors and healthcare providers will be to use the drug widely in this setting, given its high cost.

Roche announced in July that Avastin as a first-line treatment after surgery helped women with ovarian cancer live longer without their disease getting worse in the so-called ICON-7 study, but full results were only unveiled in Milan.

An earlier U.S. study in June had also shown women lived longer without cancer growth.

DWINDLING EFFECT

At 12 months, women taking Avastin on top of chemotherapy had a 15 percent reduced risk of their disease progressing, compared to those on chemotherapy alone, Perren said.

Beyond the first year the effect dwindled, with a median time to progression of 19.0 months in the Avastin group and 17.3 months in the control group. After around two years, the number of women alive without disease progression was lower in the Avastin arm.

Roche presented a different analysis for ICON-7, based on calculations that it will use for regulatory submissions. The company's analysis showed Avastin patients had a 21 percent reduction in the risk of disease progression.

"It's good data," Vontobel analyst Andrew Weiss said. "The ICON-7 study doesn't change the case materially as it confirms the efficacy from the first study."

Roche reiterated it planned to seek European ovarian cancer approval at the end of this year and submit a U.S. file in 2011.

Perren said early ICON-7 data showed an encouraging early trend in overall survival, with fewer deaths in patients treated with Avastin, or bevacizumab. But he cautioned a clear picture on whether patients lived longer would not emerge for two years.

"We need to see longer-term data. The key question is does the addition of bevacizumab to chemotherapy improve not just progression-free survival but overall survival as well," he told reporters.

Dr. Andres Poveda, of Spain's Fundacion Instituto Valenciano de Oncologia, who was not involved in the trial, echoed Perren's view that it was too early assess overall survival and urged researchers to try and identify sub-groups of patients who stood to gain most from Avastin.